Internal combustion engine



June 9, 1936.

w. F. DAVIS Filed Dec. 19, 1931 6 Sheets-Sheet 1 Q R a a v I o g INVENTOR ATTORNEYS June 9, 1936. w, DAWS 2,043,529

INTERNAL COMBUSTION ENGINE Filed'Dec. 19, 1931 e Sheets-Sheet 2 INVENTOR 7 1431/61 fflazflls I MAW ATTORNEYS June 9, 1936. w. F. DAVIS INTERNAL COMBUSTION ENGINE Filed Dec 19, 1951 6 Sheets-Sheet 3 INVENTOR IVaIZer 77JZ7az/1s fipy W ATTORNEYS June 9, 1936. w. F. DAVIS INTERNAL COMBUSTION ENGINE Filed Dec. 19, 1931 6 Sheets-Sheet 4 INVENTOR Val/er TZdI/ZS A 64/7 7 AZ'ORNEYS a fime 9, 1936. wfF. DAVIS INTERNAL-COMBUSTION ENGINE Filed Dec. 19, 1931 6 Sheets-Sheet 5 marl/1r INVENTOR lVa/Zer Z'fldZ/IS BY ATTORNEYS un 9, 193a. w. F1 DAVIS 5% INTERNAL COMBUS T I ON ENG INE Filed Deg. 19., 1931 6 Sheets-Sheet es III 7 I I I INVENTOR 46 Y 47 a/ier ffim's @MaxflM/y/ ATTORNEYS Patented June 9, 1936 UNITED STATES r 2,043,520 m'rmar. cormus'rron manta altcrEDavlnFarmingdal n.1, orto .F (1 Aviation Corporation. New York.

N. Y., a corporation 'of Delaware Application December 19, 1931, Serial No. 582,085

12 cums.

This invention relates in general to internal combustion engines and more particularly to improvements in the oiling system and in the means for driving the accessories of an engine of the multi-cylinder in-line, V or X type, wherein the crankshaft is comparatively long.

In these types of engines the'crankshaft is subjected-to an appreciable torsional vibration or oscillation due to periodically applied forces which result in changes in angular velocity, more particularly at the so-called critical or natural vibratory speeds of these shafts in the conventional internal combustion engine and flywheel, or in an aircraft engine where a propeller is provided on the end of the crankshaft where the engine power is absorbed. This largerotating mass runs at practically a constant angular velocity whereas the free end of the shaft is subject to the maximum torsional oscillation.

For reasons of simplicity, accessibility and compactness, and in an aircraft enginebecause gears and shafts and rotating masses of the ac-' cessory units to this rapid change in angular velocity with-the resultant increased wear and decreased life of all of these parts.

The object of this invention is to provide a construction whereby the subjecting of the accessory units and their driving parts to torsional oscillation and consequent damage thereto maybe substantially eliminated.

. It is also an object of this invention to provide an inverted aircooled engine having a plurality of cylinders in line, in which engine the camshaft is located below the cylinders. and to provide a camshaft'housing which will be adapted to act as an oil sump for the engine.

- Another object of this invention is to provide means whereby the bottom covering of the camshaft housing may be detached whereby mmof the wet and dry type may be interchangeable in the engine. v

A further object of the invention isto provide suitable oil drains from the upper workingparts of the engine into the sump wherein pump units are to be arranged for discharging from the sump thesc'ivening oil and the oil in the hollow camshaft into an external oil tank;

A still further'object of the invention isto arrange for the driving of the camshaft'from the flywheel end of the crankshaft, and also for driving the accessories arranged at theantiflywheel end of the engine through a shaft which takes its drive from the flywheel end of the crankshaft, and to provide an efficient lubrica- 6 tion system for all of these working parts, and

to utilize the drive of the accessory drive shaft for operating a pressure oil pump for forcing the lubricant through said shaft and to the working parts of the engine. I 10 Other general objects of the invention, particularly as far as its application to aeronautics is concerned, are to provide an aeronautical engine which is aircooled to reduce weight and which is arranged with its cylinders in line and thus cut 15 down head resistance; to provide for full visibility for the airplane pilot; which will minimize vibration, exhaust noises, and strain on the en glue and airplane parts; to provide a thoroughly reliable oiling system to the elimination of grease 20 cups, such'oiling system to include separate oil pressure and scavenging pumps; to provide for ready installation and inspection and repair or replacement of engine accessories without disturbing installation.

To this end, it is proposed'to provide a flexible accessory drive shaft for driving the accessory units and to drive this shaft from the propeller or flywheel end, where the torsional oscillations are of low magnitude, and to carry the drive go through this shaft to the anti-propeller end of the engine. The flexible drive shaft is'thus able to absorb the remaining torsional oscillations of low magnitude imparted at the front end thereof so as to not be transmitted to the accessory units 35 or their driving gears which are placed at the opposite end of the shaft. This provides for a very durable and superior arrangement, in that it has the advantages of lessening the shock on the gears and shafting when the throttle is sud- 4o denly openedor closed, with resultant acceleration or deceleration and high loading of these-- cessory driving members.

Figure 1 is a longitudinal vertical section taken through the engine and showing the arrangement of parts, and also showing the oil in dotted lines to represent the flow of oil in the lubricating ystem.

Figure 2 is a rear elevation of the engine, showing some of the accessories in rear elevation, and also a rear elevation of the cover plates for the .attachment devices for other accessories.

Figure 3 is a'view in vertical cross section of the engine, taken' through one of the cylinders,

showing the" valve and'vallve operating mecha-' nism.

Figure 4 is a view in side elevation of one of the magnetos, and also a view in longitudinal vertical section through the attachment and driving mechanism for a fuelpump and tachometer drive and of the lubricating system therefor.

Figure 5 is a view in section of the pressure oil pump, the idler gear, and the lubricating system therefor.

Figure 6 is a view in side elevation of one of the magnetos and a view in longitudinal vertical section of the pressure oil pump and drive therefor.

Figure 1 shows the plurality of cylinders arranged in line and inverted position with the crankshaft i thereabove. The engine crank case is provided with a series of partitions 4 which provide the support for the crank shaft main bearings 3 and also a support for bearings 5 in which a flexible .shaft 8 is rotatably mounted so as to be above and parallel with the crankshaft. This shaft 8 is for the purpose of driving the engine accessories which are arranged at the anti-flywheel or rear end of the engine. A camshaft 8 is arranged in parallelism with the crankshaft and accessory drive shaft and is carried in a housing I, which also forms the oil sump of the engine. The flexible accessory drive shaft 6 and the camshaft are driven by the crankshaft and obtain their drive by means of intermediate shafts and gears, the driving force of the crankshaft being taken from the front main crankshaft bearing, at which point there is the minimum torsional oscillation.

The-drive for the flexible accessory drive shaft is brought about by fitting a member II on the crankshaft so as to rotate a spur gear i2 mounted on a short shaft is, which gear in turn rotates a gear ll carried by the shaft 6. This shaft 6 extends rearwardly and forms the prime mover feral] of the engine accessories, such as magnetos, generator, fuel pump, oil pressure pump, tachometers, etc.

The driving member II also rotates the ring gear li' mounted on a shortshaft ii, the latter also carrying a bevel gear l8 which engages a bevel gear ll of avertical shaft ll, causing the latter to be rotated. This vertical shaft i8 carries a gear l9 which. meshes with a gear 20 carried by the camshaft, causingthe rotation of the latter.

The flexible accessory drive shaft 8 has been referred to as a means, for driving all of the engine accessories. This is true with the exception v the camshaft, the latter is provided with a flywheel 39 at its rear or flywheel end, and the oil pump above referred to is driven by the camshaft through the meshing of the flywheel with the oil gear. This oil pump consists of the three gears 35, 36 and 31 which is driven by the meshing of the flywheel with the intermediate driving gear 4| carried by, the short shaft 42.

In addition to the novel arrangement of parts for the purpose of producing a rugged design and the practical elimination of vibration and consequent wear on the engines parts, the accessories and the mount for carrying the engine, the englue is also provided with a lubrication system which includes a full force feed system, a complete drainage and scavenging arrangement as well as a perfect circulation system to and through all of the wearing parts of the engine and the accessories carried thereby. This system is so arranged as to completely eliminate the necessity for any grease cups either in the engine or the accessories, or any parts thereof.

The lubricant is forced into the hollow accessory drive shaft 5 which also actsas a means of oil supply to all the main and connecting rod bearings. Oil flows through the ports 5' in the shaft 6 to the drive shaft bearings 5 and thence through each of the hollow partitions to each main bearing 3. The crankshaft is provided with inlet ports I for oil at each main bearing. Thus the oil flows from the hollow partition into the crankshaft which is hollow at 22, there being a passageway 23 to the hollow crank throw at 24 and from there to the connecting rod bearing 25. The oil overflowing through the connecting rod bearings follows down the sides of the connecting rod into the cylinder and through a port 28, reaches the wrist pin bearings 21.

The forward hollow partition 4 supporting the front main bearing 3 also supports a stationary shaft 19. The oil under pressure of a pump located near the top and rear of the engine is forced through the length of the shaft 6 and after part of the oil goes to each of the other main bearings passes through the stationary shaft i9 and lubricates the ring gear I 2 before reaching the front main bearing. The oil then flows down through the lower hollow port l of the front partition and into the hollow shaft IE to furnish lubrication therefor and thence through the passageway 30 in the stationary elements of the engine into the hollow vertical shaft l8 which being driven by the meshing of bevel gears i6 and I 1 drives the camshaft through the meshing of the bevel gears i9 and 20. By-passes 3| and 32 carry the oil from the shaft i8 into the hollow camshaft 8, suitable ports being arranged therein to provide lubrication of each camshaft bearing 8. A port it is also arranged between each pair of cams to allow oil from the interior of the camshaft to spray over the valve stems and rocker arm assembly.

The oil seeping through the various bearings is collected in the camshaft housing 'i which forms an oil sump, the conduits l8 and 34 at each end of the engine beingfor the purpose of draining the oil from the crankcase of the engine; The scavenging oil collected in the cam boxispumped out by means of a three gear pump 65, 66, 61 into an external oil tank T from which it is again drawn by an oil pressure pump, located near the top at the rear end of the engine and forced under pressure through the accessory drive shaft 6 forming the oil supply conduit. The three sear pump coming the oil pump gear 31 through the shaft 42..

An oil drainage pipe 33 is held near the bottom of the sump and communicates with the pump and has its open end near the front of the sump. The rear end of the sump may be slightly lowered as at I to provide a reservoir. The gears of the three gear pumps mesh and rotate to force the oil of the reservoir and drain pipe 66 through a suitable outlet pipe into an outside oil tank.

It has been found that the torsional oscillation of the crankshaft is of a very low magnitude at the point where the ring gear H is attached thereto, and is absorbed to a considerable extent through the meshing of the gears l2 and I6 necessary to impart rotary motion to the accessory drive shaft6 and should there still be some oscillation present in the shaft 6, it will be additionally absorbed-through the length of the shaft and virtually eliminated and certainly not added to at the opposite end of the shaft.

The drive shaft 6 is adapted to drive such accessories as the generator, magneto, oil pump,- tachometer, and other accessories. A gear 6' is suitably secured-to the shaft 6 and is adapted to mesh with the idler gears '41 and 46 mounted on shafts 41 and 46 andwhich mesh respectively with gears 46' and 46 mounted on shafts 46 and 49 for driving the two magnetos-5l and 5| through the magneto shafts 46 and 46 respectively. 'The shaft" has also a gear 6| secured .thereto which coacts with a similar gear 52 to form an oil feed pump for drawing oil from either an external tank through the inlet 46' or from the sump.

The tachometer, not actually shown, may be driven by providing a socket 56 shown with its cover plate 53'. The gear 46' drives the shaft 46 and through a coupling including the spring 54 drives the magneto shaft 55 of the magneto 5|. The shaft 46 is coupled at 56 to a hollow shaft 51 in the end of which is arranged a sock-. et 56 to receive a fuel pressure pump. The drive of the hollow shaft 59, in which the tachometer drive socket 56 is arranged, is effected by a gear 60, driving an idler gear 6| mounted on a short shaft 62 and adapted to mesh with and drive the gear 63 carried by the shaft 56. The arrangement just described is shown in Figure 4 as covered by cover plates 52' and 64, the fuel pump and tachometer not being shown as they may be of any known construction, the drive for carried by a 'short'hollow shaft 64 which Ms over and is suitably splined at 65 to shaft 6 beyond the end of which the shaft 64 extends. The end of shaft 6 is socketed at 64' to form a suitable means for connecting the intermediate drive for a generator.

Oil pressure pump 6l-62 draws the oil from the exterior tank into the inlet 46'. The 011 thus drawn passes into the reservoir 44, through the coarse strainer 46 into chamber 66 of the oil pump assembly (Figure 6). From here it passes 5 into the direction indicated by the arrows into chamber 64, thence through oil gears 61-52, out into the chamber 65, and then into the reservoir 15.

Referring to Figure 9, the aperture 66 -repl resents an oilpassageway which communicates with the reservoir 15, and comprising a conduit 6'! for conveying the oil to theannulus 66 surrounding the accessory drive shaft 6. Ports 66 provide a means for conveying the oil from the i annulus to the interior of the hollow drive shaft 6 for conveying the oil to the working parts of the engine. .The rear hollow partition 4 conveys the oil from the annulus 69 to a port I6 which communicates with the passageway 62' in, the hollow lateral partition 62, a certain part of the oil also extending down through the lower portion 4' of the hollow vertical partition to communicate with and convey oil to the rear main hearing. The passageway 92 forms the conduit for oilto be supplied to various gears and working parts of the accessories mounted at the top rear end of the engine.

The accessories have no connection whatever to the anti-flywheel end of the crankshaft. The accessory drive shaft is flexible and of such proportions that it does not have any torsonal oscillations set up therein by its rotation. The imparting of any such oscillations from the crankshaft to the drive shaft is substantially eliminated by taking the drive from a point near the flywheel end of the crankshaft through ring gears in straight alignment at'right angles to the two parallel shafts.

The crankcase is of split type comprising upper and lower parts 11 and I6, and each cylinder is built separately 'and provided with suitable cooling fins, cowling and air baffles. The valve operating means comprises the single under head camshaft 6 with valve operating cams 66 which contact with the rollers 16 and 66 of the rocker arms 16' and 66' which through a suitable combination adjusting screw with a ball and socket joint or the like operate directly on the intake and exhaust valves 6| and 62 to the complete elimination of valve tappets or push rods.

What I claim is: 1. In an internal combustion engine, a plurality of cylinders inverted and in line, a crankcase, a hollow crankshaft therein, a hollow camshaft arranged beneath said crankcase, a straight, hollow shaft arranged above said crankshaft and in parallelism therewith, said upper shaft and said camshaft each being adaptedto drive a separate oil pump.

2. In an ,intemal combustion engines plurality of cylinders inverted and in line, a crankcase, a hollow crankshaft therein, a hollow camshaft arranged beneath said crankcase, a straight, hol- 2 low shaft arranged above said. crankshaft and in parallelism therewith and adapted to convey oil throughout the length of said engine, a housing for said camshaft, said housing also forming the oil sump for said engine, oil drains arranged at 70 both ends of said crankcase leading into said housing.

3. In an internal combustion engine, aplurality of cylinders inverted and in line, a crankcase, a hollow crankshaft therein. a hollow camshaft 76' rality of cylinders inverted and in line, a crankcase, a hollow crankshaft therein, a. hollow camshaft arranged beneath said crankcase, astraight, hollow shaft arranged above said crankshaft and in parallelism therewith, said upper shaft being driven from the flywheel end of said crankshaft and being adapted to (invent its other end an oil pump for forcing oil from an exterior source into said shaft, and passageways for 'oil from said shaft into said crankshaft.

5. In an internal combustion engine, a plurality of cylinders inverted and in line, a crankcase, a. hollow crankshaft therein, a hollow camshaft arranged beneath said crankcase, astraight, hollow shaft arranged above said crankshaft and in'parallelism therewith, said upper shaft being driven'from the flywheel end of said crankshaft and being adapted to drive at its other end an oil pump for forcing oil from an exterior source into said shaft, passageways for oil from said shaft into said crankshaft, means for driving said camshaft from the flywheel end of said crankshaft, and oil passageways in'said means for delivering oil into said camshaft.

6. In an internal combustion engine, a plurality of cylinders inverted and in line, a crankcase, a. hollow crankshaft therein, a hollow camshaft arranged beneath said crankcase, a straight, hollow shaft arranged above said crankshaft and-in parallelism therewith, said upper shaft being driven from the flywheel end of said crankshaft and being adapted to drive at its other end an oil pump for forcing oil from an exterior source into said shaft, passageways for oil from said shaft into said crankshaft, a housing for said camshaft, said housing also forming the oil sump for said engine.

7. In an internal combustion engine, a plurality of cylinders inverted and in line, a crankcase, a hollow crankshaft therein, a hollow camshaft arranged beneath said crankcase, a straight, hollow shaft arranged above-said crankshaft and in prallelism therewith, means, for driving sald camshaft from the flywheel. end of said crankshaft, oil passageways in said means for delivering oil into said camshaft, a housing forsald case, a hollow crankshaft therein, a .hollow camshaft arranged beneathsaid crankcase, a. straight, hollow shaft arranged abovesaid crankshaft and in parallelism therewith, means for driving said camshaft from the flywheel end of said'crankshaft, oil passageways in said means for deliveringfloil into said camshaft, a housing oil in said, camshaft intov its accessories;

for said camshaft, said housing also forming the oil sump for said engine, oil drains from both ends of said crankcase for leading scavenging oil into said camshaft housing, said camshaft driving an oil pump for forcing said scavenging oils and the oil in said camshaft into an exterior tank.

9. In an internal combustion engine, a plurality of cylinders inverted and in line, a crankcase, a hollow crankshaft therein, a hollow camshaft arranged beneath said crankcase, a straight, hollow shaft arranged above said crankshaft and in parallelism therewith, means for driving said camshaft from the flywheel end of said crankshaft, oil passageways in said means for delivering oil into said camshaft, a housing for said camshaft, said. housing also forming the oil sump for said engine, oil drains from both ends of said crankcase for leading scavenging oil into said camshaft housing, said camshaft driving an oil pump for forcing said scavenging oils and the oil in said camshaft into an exterior tank, said upper shaft driving asecond oil pump for forcing oil from said tank into said shaft.

10. In an internal combustion engine, a plurality of cylinders inverted and in line, a crankcase, a hollow crankshaft therein, a, hollow camshaft arranged beneath said crankcase, a

straight, hollow shaft arranged above said crankshaft and in parallelism therewith, means for driving said camshaft from the flywheel end of said crankshaft, oil passageways in said means oils and the oil in'said camshaft into an exterior tank, said upper shaft driving asecond oil pump for forcing oil from said tank into said shaft,

said shaft being'drlven from the flywheel end of said crankshaft, passageways leading from said upper shaft for passage of oil into said crankshaft.

11. In an internal combustion engine, a crankcase, a hollowcamshaft therebeneath, a housing Y for said camshaft, said housing also forming an oil sump, drains from said crankcase leading into said housing, a flywheel mounted on said cam-' shaft and an oil pump driven thereby for expelling the oil therein and in said housing to a point external of said engine.

12. In an internal combustion engine, a crankcase, a hollow crank shaft and a hollow drive shaft arranged thereabove and 'driven' thereby, a hollow camshaft arranged below said crankcase, a. housing forsaid camshaft, said housing also forming an oil sump, drains for oil from said crankcase to said camshaft housing. oil passageways from said upper drive shaft through said'crankshaft into said camshaft, an oil pump .driven by said camshaft for expeliing oil from said camshaft and its housing; an oil pump driven by said upper drive shaft for forcing oil into said drive shaft and the remainder of said engineand WALTER r. DAVIS. 

